Triazinylstilbene optical brightening agents



be converted into a concentrated, stable liquid form ful- 45 'finity tothe barium sulfate type and other white pigments United States Patentice Famed $51 111:

In this formula TmAzlNYLsTlLBElggAL BRIGHTENING X representsadvantageously hydrogen, or the methyl AGENTS group: HeinrichHausermann, Riehen, near Basel, Switzerland, 1 p e e a lower alkyl offrom 2 t0 4 Ca n at s assignor to J. R. Geigy A.G., Basel, Switzerland 5containing from two to three hydroxyl groups, one of No Drawing. FiledDec. 18, 1964, Ser. No. 419,571 which is advantageously in ,B-positionto the respective Claims Priority, application Switzerland, 1959, aminonitrogen atom, not more than one hydroxyl 80,847/ 59 group being linkedto each carbon atom of R 4 Clalms' (CL 260-440) R represents loweralkyl, advantageously the methyl 10 group. This application 18 acontinuation-in-part of my copending application Serial No. 70,124 filedNov. 18, 1960. Particularly valuable brightening agents correspond toThe invention concerns liquid, concentrated brightenthe formula ingpreparations, processes for the production thereof wherein and forltheproducllon of aFtlve substanqes suitable there- X represents a memberselected from the group consistfor, their use, particularly in the paperindustry, and the g of H and CH materials, in particular the finepapers, the appearance of R represents which is improved with their aid.1

Liquid brightening preparations having a high content 2 H H2OH of activeingredient are desired by industry because they OH are simple to use andmore easily incorporated into texand tile or paper treatment liquors.ThlS is the case prin- R2 represents lower alkyll ci all in the a erindustry, particularly the fine paper in clusl ry, e.g. f r t heproduction of sized and filled papers Of 'P Compounds of Formula thoseare Preferred and of coated fine papers the appearance of which is to beX 15 hydrogen and 2 IS an alkyl Iadleal improved by means ofblue-fluorescent brightening agents. talnlng at 4 a b a oms.

Nowadays, agents, the blue fluorescence of which is The activeIngredients afieeldlng t0 the Invention, P more of a violet shade (whichappears usually pinkish to tlcularly these Prepared Wlllh Preferredcomponents, have the observer) are preferred to those of a bluefluorescence a e to efi y t0 the additives in fine P p in f i h h d 40particular to silicate fillers such as china clay, talcum or A primaryrequirement of such industrial liquors cork kaolin, to calcium sulfatefillers such as the so-called satin taining active brighteningingredients is a high degree of Whlte, to ealelum earbqfiate a dBlancofiic (barium sulstability even during long storage. late) as wellas to the binding agents usual in paper coat- Moreover, not everybrightening ingredient which can masses $11011 as d graded starches,carboxymethyl celluloses and certain synthetic resin dispersions.

A particular advantage of the compounds according to the inventionresides in the fact that their brightening activity does not suffer evenin solutions with a relatively high content of alum and the likealuminum salts, as it occurs in the strong backwater (white Water) ofpaper mills.

Hitherto known brighteners when introduced into such backwater, areusually precipitated in the form of their yellowish aluminum salt, andthe result is an undesirable discoloration of the paper obtained frompulps processed with such backwater.

Concentrated aqueous solutions of the compounds acfills otherrequirements made in the paper industry. As organic solubility promotersare necessary for the production of liquid forms of active ingredientwhich, as a rule, reduce the affinity to the material to be brightened,the blue-fluorescent active ingredients employed in the 50 manufactureof fine papers must have a high affinity for at least one component 'ofthis material. A good afis important for filled fine papers and,particularly, for coated fine papers.

The present invention is concerned primarily with active substanceswhich are not only suitable for use in the h preparation in concentratedliquid form and are stable in f to t e llwentlen, as y are Used InIndustrial apthe same even during long storage times, but which alsolhcatloll for bnghFenmg Purposes, are e for a much have good aflinity tothe aluminum sulfate or barium sullonger time even III the P e f saltsthan are confate type additives and other white pigmentsconventioncentrated sqlutlons of known Compounds Pertaining t0 the allyused in the fine papers. class of s-triaziny-l-substituted stilbenes.

The active compounds of such brightening prepara- More in particular,the compounds according to the intions according to the inventioncorrespond to the formula vention can be incorporated into liquidpreparations in high-concentrations, of 25% and higher, e.g. bri-ghtenerstock solutions for industrial purposes, especially in the paper andtextile industries, even when they still contain The content ofinorganic salt of the sodium chloride type in the liquid brighteningpreparations according to the invention is maximally, calculated forthecase of sodium chloride, about to 100% of the weight of the opticalbrightening agent, depending on the desired concentration of the latterin the preparation.

Known stilbene brighteners such as those described in US. Patent3,012,971 to Gessner et a1 require careful elimination of the saltcontent to a permissible amount of less than 5%, if industrial liquidswith the above-1 mentioned concentrations of brighteners are to beprepared. Otherwise, at sodium chloride contents of 5% and higher,precipitation of the bri-ghtener takes place,-

Which may lead to spotty effects on the treated materials.

Concentrated, liquid forms of known brightening agentsas well as thoseaccording to the invention and the active ingredients suitable thereforare obtained by-- (1) reacting in an aqueous medium in any orderdesired,soluble salts of 1 mol of 4,4'-diaminostilbene-2,2' disulfonic acid andof 2 mols of an 'aminobenzene, with 2 mols of cyanuric halide and (2) inthe resulting condensation product dispersed in the reaction medium,reacting the remaining halogens with a lower molecularsecondaryalkanolamine, isolating the resulting product to separate the same asmuch as possible from ionogenic salt' (NaCl) and other byproducts of thereaction, and

(3) subsequently admixing the product with water as well as certainorganic solubility promoters which are easily soluble in water, andthen, if necessary, filtering oif solid precipitates from theconcentrated solution of active ingredient.

Conventionally, the production of concentrated liquid preparationsrequires concentrated aqueous solutions of the active ingredient whichcan only be produced in the absence of larger amounts of inorganicsalts, especially sodium chloride. In the known methods of preparations,

the inorganic salts must be removed, for example, by

dialysis and the dilute solutions of the active ingredients are thenconcentrated by evaporating or steaming off the water.

Or, in lieu of using dialysis, the reaction productis isolated in theform of its free acid which can be washed with water -to remove allelectrolytes present therein. The free acid must then be converted to analkali metal or an ammonium salt which is then used for preparation ofstable, relatively concentrated solutions.

By adding organic solvents to the concentrated aqueous preparations ofthe end products so obtained, concentrated solutions of the activebrightening ingredients are obtained, sometimes with'further separationof precipitates formed, which solutions must be further clarified byfiltering off such precipitates.

The concentrated, liquid brightening preparations according to theinvention and the active ingredients suitable therefor are obtained inthe manner described.

hereinbefore, but with the following improvements:

(at) A soluble salt of 1 mol of 4,4'-diamino-stilbene- 2,2'-disulfonicacid is reacted with 2 mols of a 4-aminophenyl sulfonic acid, the phenylradical of which can be further substituted by a methyl group, and with2 mols of cyanuric halide;

(b) The resulting intermediate condensation product is preferablyisolated, e.g. by adding to the reaction medium inorganic salt(preferably NaCl) in amounts of about 5 to 10% by weight calculated ontheweight of the reaction. medium, and again dispersedin water;

(c) The reaction of the remaining halogens is carried out withsimultaneous or subsequent admixture of organicsolubility promoters.which areeasily soluble in.

Water, with a lower molecular secondaryalkanolamine which contains analkyl radical as nitrogensubstituent;

(d)i If no isolation of the intermediate condensation.

product. has been effected, the final product is isolated by saturationof the reaction medium with inorganic salt (NaCl), about 30% beingusually required, calculated on the weight of the final product.

Preferred brightening preparations and activeingredients suitabletherefor according to the. invention are obtained by using,4-aminobenzeneal-sulfonic; acid.

More in detail, the reaction'of 2 mols of an alkali metal salt ofp-aminobenzene sulfonicacid is carried out in the cold with 2 mols offinely distributed cyanuric halide, in particular cyanuric chloride, ata pH of at most 7, andv liberated acid is neutralized, for example, withdilute alkali carbonate or alkali bicarbonate solution, until theprimary amino groups have disappeared. Then the two mols of the alkalimetal'salt of 4-(4,6-dihalogen-.

1,3,5 -triazinyl- (2 -amino -benzene-1-sulfonic acids are. reacted attemperatures of from 15 to 60- C. with the solution of 1 mol of analkali metal salt of 4,4-diamino- 1 stilbene-2,2'-disulfonic acid untilthe free amino groups have dis'appeared, liberated acid. beingneutralized. Finally, the solution of the alkali metal sa-ltvof4,4'-bis- .[4 (4'-sulfophenyla'mino)-6-halogen 1,3,5-triazinyl-(2)-amino]-stilbene-2,2'-disulfonic acid {obtained is reacted-- at elevatedtemperature (70 to C.) with an. excess of the secondaryalkanolamine.until the halogens bound" at the triazine ring have all been replaced.This last reaction can be performed 'inthe presence of'an acid- 1binding nitrogen base.

The reaction can be performed-under otherwise .com- 1 parable conditionsin reversed 'order'by first reacting the solutionof the alkali metalsalt of 1 mol of 4,4-di- 1 aminostilbene-2,2-disulfonic acid vwith 2mols of a cyanuric halide, advantageously cyanuric chloride or, 7 also,cyanuric bromide, until the primary amino'groups I have disappeared,then reacting the condensation product.

with the solution of'the alkali metal salt of 2 mols ofa4-aminobenzene-1-sulfonic acid and, finally, with an excess of the abovedefined alkanolamine.

The moist intermediate condensation products in step (c), or themoist'final products obtained in step (d),

if precipitated as free acids in mineralacid solution,'can

be reacted with excess alkanolamine, in the presence of; tertiarynitrogen base, whereby vammonium'salts of the end product with thesenitrogen bases are obtained. These ammonium salts canv also be used asactive ingredients in the preparations according to the invention.

In the above-described reaction, the necessary amount 7 of solubilitypromoter depends to a greatextent on its, properties, butis considerablylower (e.g. less than half), than the amount of solubility promotersrequired in the.

known liquid high concentratejbrightening preparations. Such promotersare preferably liquid substances which are easily miscible with water;amounts of about 25 to I calculated on the .weight' of the solid activein gredient according to the invention are suflicient for thepreparation of aqueous solutions having a content ofethyl,di-fi-hydroxycthylthioether, ethylene glycol di- S-hydroxyethyl ether,diethylene glycol'monomethylor mono-- high molecular polyglycolethylether, various not too ethers; easily water soluble amides of carbonicacid or of carboxylic acids such as e.g., urea, N-dimet'hyl-methyh,-ethyl-, methoxyethylor ethoxyethyl-urethane, formamide,N-dimethyl-formamide, acetamide, N-diethyl acetamide, N-diethylacetamide, N-d-imethylor N-diethylbenzamide, acetic acid diethanolamide,benzoic acid diethanolamide; alkanolamines such as monoethanolamine,diethanolamine, triethanolamine, N-methylor Naethylmonoor-diethanolamines, propanolamines Instead of one of these compounds, itis often advantageous to use mixtures thereof. Ethylene glycolmonomethyl and monoethylethers are preferred organicsolubility'promoters inthe preparation dfconcentrated, liquid forms ofbrightening agents according to the invention.

Further details regarding the production and use of the activeingredients and liquid forms of brightening agents according to theinvention can be seen from the following examples, which illustrate theinvention without limiting it. Where not otherwise stated, parts andpercentages are given .by weight. The temperatures are indegreescentigrated. The relationship of parts by weight to parts by volume isas that of grams to 'cubic centimeters.

I do 3N3 by the successive addition of 26.5 parts of sodium carbonate.When no more free sulphanilic acid can be traced, 150 parts of sodiumchloride are added to the suspension obtained, the white product isfiltered off, washed with 5% sodium chloride solution and acetone anddried in vacuo at -45.

The preparation obtained can be used in the usual way for the whiteningof cellulose substrata. Compared with products in pulverulent form, thisliquid preparation has the advantage of being more conveniently measuredand of being much more quickly distributed homogenously in the dyeliquor. When used in the paper industry, the preparation has theadvantage of a good affinity to the fillers used in paper finishing suchas e. g. kaolin, china clay (aluminum silicate), talcum and calciumsulfate. In the production of fine papers such as, e.g. chromo papers,considerably more brightened results are obtained on using thebrightening preparation described than when the usual paper brightenersare used.

If in this example, the 200 parts of N-ethyl-l-arninopropane-2,3-diolare replaced by 250 parts of N-butyl-lamino-propane-2,3-diol, then thetetrasodium salt of 4,4- bis-[2"-N-butyl-,8,' -dihydroxy-propylamino-4"(p sul- H o o H-C Hr-N S0 aNa 1]IC Hz-CHzOH H2011 1H, om omoH CH3 CH;

148 parts of 4,4'-diaminostilbene-2,2'-disulphonic acid are dissolvedwith 32 parts of sodium hydroxide in 2000 parts of water. 290 parts ofthe sodium salt of :1-[2',4'-dichloro-1,3',5 '-triazinyl-'(.6 -amino]benzenel-sulphonic acid are added While stirring at 50 within 1 hour andthe acid liberated is neutralised by successive additions of a solutionof 43 parts 'of sodium carbonate in 250 parts of water. The whole isthen stirred at 6 0 until after about 3 hours, no more free, primary,ar-omatically bound amino groups can be traced. 200 parts ofN-ethyl-laminopropane-2,3-diol are then added to the white suspensionobtained which consists of the tetrasodium salt of 4,4-bis-[2"-chloro-4"(p-sulphophenyla-mino) 1",3", 5"-triazinyl(6")-amino]-stilbene-2,2'-disulphonic acid, and the whole is heated for90 minutes at 8590 while stirring. In this way,-a yellowish to palebrown coloured, clear solution is obtained which contains the desiredtriazinyl derivative of the formula given above.

To convert it into a liquid preparation containing 37% of activesubstance, the solution is concentrated under reduced pressure to 1000parts and then converted into a relatively thinly liquid solution 'byheating with 240 parts of ethylene glycol monomethyl ether. Precipitatedsodium chloride is filtered off at 40 and the clear filtrate is madeupto a weightof 1300 parts with water.

The sodium salt of l[2'-4'-dichloro-1 ,'3','5 triazinyl- (6 amino]-benzene-4-sulp'honic acid 'mentioned'above is produced as follows: 93parts 10f cyanuric chloride are dissolved in 400 parts by volume ofacetone and the solution is poured while stirring into 1000 parts of icewater. A solution of 97.5 parts of the sodium salt of sulphanilic acidin 500 parts of water is poured within 30 minutes at 0 while stirringwell into the fine cyanuric chloride suspension soobtained and the acidliberated "is 'neutralised fop'henylamino)-1",3",5" triazinyl-(6amino]-stilbene-2,2-disulfonic acid is obtained in an analogous manner.As a brightening agent it is an equally active, stable, liquidpreparation.

Example 2 37 parts of cyanuric chloride are dissolved in 200 partsofacetone and the solution is poured while stirring into a mixture'of400parts of crushed ice and 400 parts of water. A solutlon of 37 parts of4,4-diaminostilbene-Z,2'-disulfonic'acid in 500 parts of 1.6% causticsoda lye is poured within 30 minutes while stirring into the cyanuricchloride suspension obtained. The acid liberated is neutralized by thesuccessive addition of 16.8 parts of sodium bicarbonate. As soon as nomore free 4,4-diaminostilbene-2.,2- disulfonic acid can be traced, 39parts of the sodium salt of sulfanilic acid are added and the mixture isheated at 45-55 while keeping the reaction neutral with 15% aqueoussodium carbonate solution until a sample tested by dlazotisation showsthat no more free sulfanilic acid is present. In this Way, a suspensionof the tetrasodium salt of 4,4'-bis-[2"-chloro-4 (psulfophenylamino)-l,3",5"-triazinyl-(6")-amino]-stilbene-2,2'-disulfonic acid is obtained.

This intermediate product is converted into an easily filtrable form bysalting out with sodium chloride added in an amount of 10% by volumecalculated on the total volume of the reaction mixture, the precipitateis filtered off under suction and dried in vacuo at The active contentis ascertained by analysis of the organically bound chlorine (totalchlorine less ionogenic chlorine).

An amount of the resulting dry crude, easily filtrable intermediateproduct which contains 20.5 parts of the compound of the formula NH- S O3N8 SOsNa SOzNa Cl is added to a solution of 11.9 parts ofN-ethyl-l-aminopropane-2,3-diol in 25 parts of water and 15 parts ofethylene glycol monoethyl ether and the whole is heated for 4 hours at80-90. A clear, stable preparation is obtained which contains thebrightening agent described in Example 1 as active component.

Liquid preparations having an equally good action are Similarly activebrightening preparations are obtained if in this example, the 37.4 partsof 3-methyl-1-ami'no-:

obtained if the N-ethyl-1-amino-propane-2,3-diol is replaced byequivalent amounts of the following bases:

N methyl-l-amino-propane-i2,3-diol N ethyl-tris(hydroxymethyl)aminomethane (prepared from Tris (hydroxymethyl)-aminomethane and ethylbromide) and N- butyl-l-aminopropane-2,3-dil.

Example 3 HO CH-CHz-l? AOaNa 37 parts of cyanuric chloride are dissolvedin 200 parts by volume of acetone and the solution is suspended in amixture of 500 parts of ice and 400 parts of water. The solution of 37.4parts of '3 methyl-1-aminobenzene-4- vtriazinyl-(6)amino]-stilbene-2,2-disulfonic acid benzene-4-sulfonic acid are replacedby 37.4 parts of -2- methyl-1-aminobenzene 4-sulfonic' acid.

Example 4 The procedure described in Example 1 is followedbut thetetrasodium salt of 4,4-bis[2 (-N ethy1-}8,'y dihydroxypropylamino)4"-(-psulfophenylamino)r1",3",5-

tained is separated in: asolid form by saturating with sodium chloride.It is dried in .vacuo at 80.

In this way, thebrighetening agent is obtained as a very easily watersoluble, pale yellow'powder. To produce rPoni-cnorr CH9 CH zQH I liquidpreparations containing %of active ingredient;

thesubstances listedin the following Table in the given sulphonic acidand 8 parts of sodium hydroxide in 300 parts of water is poured into thecyanuric chloride suspension so obtained while stirring and the acidliberated is neutralised by the successive addition of 10.6 parts ofsodium carbonate. The almost white suspension is stirred at 0 until adiazotised sample shows that'there' is no more primary, aromatic aminepresent. 70 parts of sodium chloride are then added and the precipitatedsodium salt of2,4-dichloro-6-(3-methyl-4'-sulphophenylamino)-1,3,5-triazine isisolated by filtering off under suction. The product can be dried'atroom temperature in vacuo over sodium hydroxide or dehydrated calciumchloride, or it can be worked up direct in a moist condition.

37 parts of 4,4'-diaminostilbene-2,2'-disulphonic acid can be traced.After adding parts of sodium chloride,

the pale grey suspension is quickly heated to 80, then cooled to 30 andthe tetrasodium salt of 4,4'-bis-[2"- chloro-4"-(mmethyl-p-sulphophenylamino) 1",3,5"-

triazinyl-(6")-amino]-stilbene-2,2-disulphonic acid ob,-- tained isfiltered ofi. The product is dried in vacuo at:

70; 1055 parts of the dried intermediate product are added to a mixtureof 90 parts of ethylene glycol monor ethyl ether, 28.6 parts ofN-ethyl-amino-propane-Zfi-diol, 33 parts of triethanolamine and 140parts of water. and the whole is heated for 2 hours at 80-90". A stable,

pale brown solution is obtained which contains the pro duct of theformula given above as active substance.

If in this example,'the 90 parts of ethylene glycol monoethyl ether usedas solubility promoter are replaced.

by the same amount of the following glycol derivatives: ethylene glycolderivatives: ethylene glycol monomethyl ether, diethylene glycol,ethylene glycol-di- B-hydroxyethyl ether, diethylene glycol monomethylether, diethyl-- ene glycol monoethyl ether, then stable, liquidbrighten-i ing preparations containing about 30% of active substance arealso obtained.

ratios "can be used:

Brighten- Water, mg agent, parts Solubility promoter parts 30 50 20parts urea.

30 60 10 parts dimethyl tormamide.

30 5O 20parts dithyliormamide.

30 V 55 15 parts diethylacetamide;

30 60 IOparts.dimethylbenzamide.

30 50 20 parts diethanolamine.

30 5O 20 parts triethanolamine.

30 55 15 parts monoethanolamine.

'30 60 10 parts sodium salt of m-xylene sulphonic acid.

30 60 20 parts cane sugar. 1

30 60 lo'parts pentaerythritol. 5

30 50 5 parts sulphite waste liquor+l5 parts formamjde.

30 50 20 parts glycerol.

30 50 20 parts propylene glycol-1,2.

30 50 20 parts ethylene glycol monopropyl ether.

30 50 10 parts ethylene glycol monomethyl ether+l0 parts ethylene glycolmonobutyl ether. I

30 501 20 parts di-B-hydroxyethylthioether. I I

330 511 10 parts urea-H0 parts N-di:

methylethylurethane.

30 50 4 20 arts N-dimethylme- 30 50 20 parts acetamide.

30. 50. 20 parts acetic acid diethanolamide.

30 50 20 parts benzoic acid diethanolamide. I

Preparations with a higher content of active substance 7 canbeproducedin an analogous manner. Thus, starting from the brightenermentioned above, the following combinations with 37.5% or even 40%content ofactiv substance can be pr-oducedz. I

Brighten- Water,

mg agent, parts Solubility promoter parts 37. 5 52. 5 10 partsdimethylformamide. 40 45 15 parts dunethylformamide. 40 45 15 partsmonoethanolamine. 37. 5 42; 5 20 parts ethylene glycol. 37. 5 42. 5 20parts 1,4-butane diol. 37. 5 42. 5 20 parts'polyethylene glycol ofmolecular weight 400.

Example ing mass than with the same coating mass which, howpotassiumchloride is employed to Salt out the potas ever, contains a knownmarketed paper brightening agent. sium salt from the aqueous solution ofthe tetrasodium Example 8 salt of4,4abis-[2-(N-ethyl-,B,'y-dihydroxypropylamino)- Surface coating of acutwork printing paper.4-(p-sul-fophenylamino)-1",3",5f-triazinyl-(6")-amino] 5 Paper intendedto carry illustrations is coated in the -stilbene-2,2'-disulfonic acidproduced according to EX- usual manner with the following coating mass:ample The isolated potassium salt is dned and 50 parts of china clay(aluminum silicate white pigment) verted into a stable, liquidpreparation by heating with 0 ethylene glycol monoethyl ether and waterin a ratio of z iiigg Starch as bmdmg agent 3:25 thls case Solventemployed can be 0.1 part of a brightening agent obtained according toreplaced by other hydrotropic substances such as, e.g. Example 1'dimethyl formamide or diethanolarnine.

A paper having an excellent white effect is obtained in Example 6 thisDyeing in the paper mass of papers filled with white I claim:

1. A member selected from the group consisting of a pigment:

An aqueous slurry containing 85 parts of cellulose, 15 compound of theformula H035 IIIH NHQ-SOaH \N 03H 03H I|ICH7-R1 parts of an aluminumsilicate white pigment of the trade and the alkali metal and ammoniumsalts thereof; wherein name China Clay and 0.15 parts of a liquidbrightening X represents a member selected from the group consistingpreparation obtained according to Example 1, is worked of hydrogen andmethyl,

up in the usual way with 2 parts of rosin size and 4 parts R1 rep ese tsl wer alkyl of from two to four carbon of aluminum sulfate into a papersheet. A filled paper atoms Containing from two to thret? free Y Y ofvery white appearance is obtained in this manner. groups not more thanone hydroxyl group bemg hnked to each carbon atom of R R representslower alkyl.

Example 7 p 40 2. A member selected from the group consisting of aSurface coatmg of a chromo paper. compound of the formula H03S- 1TIHNHSO3H N N X N/ NHCH=CHNH N X \=N N:/ 121-0112 l g g I \N 0311 03HIII-CH2 i II; R2

The following coating mass can be used, for example, and the alkalimetal and ammonium salts thereof; wherein to produce a Chr m pap r: Xrepresents a member selected from the group consist- 20 parts of chinaclay (aluminium silicate white pigment) mg of hydrogen and y 20 parts ofsatin white (calcium sulphate white pigment) 1 represfints l w alkyl ofm two to four carbon 2 parts of a synthetic resin dispersion of thetrade name atoms contalnlng two to three free y y Acronal D 500 producedby Farbenfabriken Bayer, in s q p q of Whwh is in fl-p to e respectiveLeverkusen, Western Germany, 0 amino n trogen atom, not more than onehydroxyl 2 parts of casein, group being linked to each carbon atom of R56 parts f water, R represents lower alkyl. 0.1 part of the brighteningagent as obtained according 3. A member selected from the groupconsisting of a to Example 2. compound of the formula A considerablywhiter paper is obtained with this coatand the alkali metal and ammoniumsalts thereof.

4. A member selected from the group consisting of .a and the alkalimetal and amn lj qninm salts-thereof.

compound of the formula HOaS-Q-IITH @sihm HOCHz-OH-CHz-N $0111 $0311 NOHz-OH,CH2OH n ()H 0H, 7 on, n 011 7 CH, n C2H I (5: 5

References Cited by the Examiner FOREIGN PATENTS 208,955 7/1957'Australia; 1,274,846 9/1961 France.

OTHER REFERENCES WALTER A. MODANCE, Primary Exa hziner.

JOHN D. RANDOLPH, Examiner.

1. A MEMBER SELECTED FROM THE GROUP CONSISTING OF A COMPOUND OF THEFORMULA